Timeline (Military Calender)
Note: There is a 366 year difference between the ME universe (at the end of the Reaper War) and Halo universe (at the end of the Human-Covenant War). I did not take this into account as that would have taken too much time and effort that I don't desire to put in. However, I believe that-for the most part- the timeline is relatively accurate. Please PM me if you notice any discrepancies in the timeline. Thank you.
Pre 1,000,000,000-1,000,000,000 BCE
- Various empires are established including: the Xel'Naga, the Engineers and a plethora of other galactic civilizations.
- The Leviathans arrive, destroying the previous galactic empire and establishing a great civilization spanning the galaxy. They create the Reapers who eventually turn on their masters and exterminate them. This is the 1st Cycle.
- The Reapers create the Mass Relays and Element Zero in order corral organic races into advancing along a predetermined path of technological advancement and proceed to wipe out all organic life every 50,000 years.
1,000,000,000-150,000 BCE
- Precursors dominate the galaxy without the aid of Mass Relay, and subsequently, Element Zero technology.
- Reapers arrive for the 13th Cycle's Pan-Galactic Reaper War and are annihilated by the Precursors. During the war the Precursors destroy the Leviathan of Dis and create the Great Rift Valley when they disable a Reaper near the planet Mnemosyne, the Reaper creating the Valley when it crashes onto the planet Klendagon.
- Precursors study the Mass Relays before hiding them. The Mantle of Responsibility is created in the wake of the 13th Cycle's Pan-Galactic Reaper War as a response to the threat of extra-galactic invasion.
- Forerunners and Humans are created
- Forerunner-Precursor War begins when the Forerunners discover that the Precursors planned to exterminate them.
298,000 BCE
- The Arthenn progress rapidly on the technological tiers, however they are constrained by the remnants of Reaper artifacts left behind, forcing them along the predetermined path. They are caught in the crossfire of the Forerunner-Precursor War and are subsequently exterminated.
150,000 BCE
- The Forerunners dominate the galaxy
- The Reapers linger on the edge of the galaxy, wary of the Forerunners due to their experiences with the Precursors.
125,000 BCE
- The Thoi'han and the Inusannon civilizations encounter the Flood and the ensuing conflict destroys both civilizations. Their destroyed ships are scattered all over the planet Eingana, their cores creating an environment in which Element Zero is created. The result is that many indigenous species go extinct, the rest developing biotic powers.
110,000 BCE
- The Human/Prophet-Flood War and the Forerunner-Human War begin.
109,000 BCE
- The Human-Forerunner War ends with humanity defeated by the Didact and his forces
105,000 BCE
- The Flood is rediscovered
- The twelve Halo Arrays begin construction and the Librarian begins to index all life across the galaxy.
- The Didact is imprisoned for his opposition to the construction of the Rings.
100,300 BCE
- Flood-Forerunner War begins
100,043 BCE
- Mendicant Bias is constructed
- The last Precursor is discovered
100,000 BCE
- Didact is freed by Bornstella. Bornstellar becomes the Iso-Didact.
- Mendicant Bias betrays the Forerunners, forcing the destruction of five of the original twelve Halo Arrays.
- A Forerunner artifact is buried in the Earth's crust underneath what is Africa.
- 343 Guilty Spark is constructed.
- Offensive Bias is constructed to counter Mendicant Bias.
- The Ur-Didact attempts to create a Promethean army using the army of Forerunners under his command and the fledgling human race. He is stopped by his wife, the Librarian, and imprisoned in Requiem so that he may ponder his mistakes and guide humanity upon his discovery.
- The Halos are fired when the Mendicant Bias led Flood ships breach the Forerunner's inner colonies, wiping out all sentient life.
- The Flood-Forerunner War ends with the destruction of Mendicant Bias' armadas and the subsequent shattering of Mendicant Bias itself, its constituent parts separated. Two of its parts arrive on the Ark and the Prophets' homeworld.
- The Reapers invade the galaxy after the conclusion of the 14th Cycle. They first release the Mass Relays and construct more Relays to replace those destroyed. Using the Relays they seek out and destroy the any remnant of Forerunner and Precursor technology that they can, but are unable to completely erase the civilizations due to constraints posed by time and Mass Relay travel. Additionally, they construct the Citadel as a means of attacking the galaxy from the center out as opposed from the outside in, one of the principal reasons they failed against the Precursors.
- The galaxy is reseeded—new species developing with the old. The Asari are humanity's cousin, their DNA derived from human as the Forerunners attempted to create a species hardy enough to survive the coming tribulations.
68,000 BCE
- The Protheans rise to prominence and establish a galactic empire with the Citadel as their capital.
- The Metacon War- The Protheans uncover a Forerunner Shield World, designation Pantheon, and do battle with the escaping Prometheans. The Protheans eventually manage to prevail, sealing the Shield World and developing a healthy anti-AI stigma.
48,000 BCE
- 15th Cycle's Pan-Galactic Reaper War. The Prothean Javik hides with a million Prothean soldiers in an underground bunker on what is now Braxis.
30,000 BCE
- Homo Sapiens, the direct descendants of pre-historic humans becomes the dominant species.
13,000 BCE
- The Turians begin to develop civilization.
2200 BCE
- San 'Shyuum Civil War
2100 BCE
- The San 'Shyuum Civil War ends with about 1,000 Reformists leaving the home world with the dreadnought.
1900 BCE
- The Krogan home world is devastated by nuclear fallout by the Krogan themselves as the Krogan war against each other.
1800 BCE
- A supernova propels the Mu Relay out of position. The Rachni discover it.
938 BCE
- Sangheili-San 'Shyuum War
852 BCE
- Writ of Union ends the Sanheili-San 'Shyuum War
785 BCE
- Taming of the Lekgolo
784 BCE
- The Covenant resort to orbital bombardment after the Mgalekgolo manage to kill an Arbiter and stall the Covenant advance for the better part of a year. The bombardment forces the Te natives to surrender, resulting in their induction into the Covenant after the Lekgolo colonies that fed upon the Forerunner relics were exterminated.
520 BCE
- The Salarians discover the Citadel and open diplomatic relations with the Asari.
500 BCE
- Citadel Council is formed.
- First Contact with the Volus is made. Eventually, the galactic currency known as the credit is established with the help of the Volus.
- The Turian Unification Wars occur. Eventually, the warring factions are unified under the Turian Hierarchy. Discontent and enmity continue for decades.
- The Volus are the first species to gain an embassy on the Citadel as opposed to a Council Seat.
- First Contact is made with the Batarians who later gain an embassy a century later.
- The Elcor are discovered by the Asari, and are directed to the nearest Mass Relay in an effort to connect them with the galaxy. Trade is established between the Elcor and the Citadel, the Elcor gain an embassy on the Citadel.
- First Contact is made with the Hanar and the Quarians; both gain embassies at a later date.
1 CE
- Rachni Wars
7 CE
- The Covenant infiltrate a Dyson Sphere and encounter the Huragok. They are quickly assimilated into the Covenant hierarchy.
80 CE
- The Rachni Wars continue; the Salarians uplift the Krogan, using them as the vanguard of the Citadel Council. The Krogan's hardy physiology enable them to combat the Rachni on their worlds, destroying the Rachni by eliminating their ability to reproduce.
300 CE
- The Rachni are declared "extinct." The Citadel Council rewards the Krogan with a new home world; consequently, the Krogan population explodes. There is still a fear of invading species, so new safety measures are put in place, ensuring that a new Relay will not be activated for almost 3000 years.
693 CE
- The explosion of the Krogan population leads to the formation of the SPECial Tactics and REconnaissance branch of the Citadel: SPECTRE.
- The Salarian Beelo Gurji is the first Council Spectre, appointed the position in 693 CE.
699 CE
- Krogan Rebellions
700 CE
- The Citadel makes First Contact with the Turians and acquires their aid in halting the rampaging Krogan. The Krogan respond to the Turian through the brutal annihilation of Turian colonies with WMDs, aggravating the Turians and causing the Turians to fully commit to halting Krogan aggression.
- Sometime after the Turians join the galactic community, the Volus become a Client Race of the Turian Hierarchy.
710 CE
- Imitating the success of the Krogan against the Rachni, the Turians utilize the Salarian made Genophage to destroy Krogan reproduction.
800 CE
- The Krogan Rebellions largely end.
- The Turians rise to take the place of the Krogan as galactic peacekeepers, law enforcement officers and military personnel.
- The Citadel Conventions are drawn up in regards to the devastation and havoc wreaked by the Krogan's WMDs. The Conventions were used to classify WMDs into tiers and outlawed their usage on garden worlds or sealed space stations.
900 CE
- In recognition of their service during the Krogan Rebellions, the Turians are granted a Council Seat.
1112 CE
- The Yanme'e are discovered by the Covenant. They are swiftly conquered and inducted into Covenant society.
1342 CE
- The Covenant discover the Kig-Yar. The resulting war ended with the Letters of Marque, essentially making the Kig-Yar the privateers of the Covenant and occasionally hiring them as mercenaries.
1400 CE
- Exponentially growing industry on the Drell home world Rakhana deteriorates the biosphere.
1600 CE
- The first Collector sightings are reported in the Terminus Systems. These claims are discredited as unsubstantiated rumors and gossip.
1895 CE
- The Geth, mechanical laborers, utilized by the Quarians, are assaulted by their Creators as they feared that the now sentient Geth would revolt against their makers. The Morning War saw the Quarians driven from their worlds, forced to live in seclusion aboard the Migrant Fleet. The Citadel Council punished the Quarians by closing the Quarian embassy on the Citadel.
1921 CE
- The Geth begin work on a super-structure that would house and run every Geth in existence. The completion of the structure would result in the Geth reaching their maximum processing capability as a collective group.
1945 CE
- Conclusion of World War II and the establishment of the United Nations.
1961 CE
- Yuri Gagarin becomes the first human to travel in space.
1969 CE
- Apollo 11 lands on the moon, making Neil Armstrong the first human to walk upon Earth's satellite and any other astronomical object other than Earth.
2000 CE
- The Hanar and Drell initiate First Contact. By this time the Drell's home world is debilitating, and the Drell face years of hardship in the future. The Hanar begin a massive evacuation of the planet, saving 375,000 Drell and transport them to the Hanar home world Kahje. The remaining 11 billion Drell war with each other and perish, but the species is saved from extinction.
2080 CE
- Man's first colony is established on Mars, soon found by the colonization of the Jovian Moons orbiting Jupiter.
2125 CE
- The Yahg are contacted by Citadel ambassadors, who are brutally murdered and devoured by the Yahg. The Council then declares the planet Parnack off-limits.
- Soon after the Shadow Broker takes in a stray Yahg, training the Yahg in the arts of intelligence collection. Eventually the Shadow Broker attempts to terminate Operative Kechlu, but the plot is thwarted, leaving the path of ascension open for the Yahg.
2137 CE
- The Prothean Javik and 10,000 of his soldiers are uncovered. Javik brings news of the Reapers, but is ignored by the general public. However, the Citadel Council questions Javik and determines that his story is plausible and beings preparing for the inevitable return of the Reapers. Part of the preparation is a massive influx of security at the Relays, increased cooperation between Citadel races, larger navy sizes etc. All these efforts are furthered by Prothean scientists who contribute their technology. Construction of the Catalyst and an anti-Reaper virus begins.
- The Protheans establish themselves on Braxis and see a population boom. They will reach several dozen million by the end of the century.
- Samara's three daughters are diagnosed as Ardat-Yakshi. Two concede to exile while Morinth flees. Samara takes the oath of the Asari Justicars in response, and spends the next 346 years pursuing her daughter.
2142 CE
- The Unggoy are discovered by the Covenant and are inducted into the religious organization.
2160 CE
- Jovian Moons Campaign
2162 CE
- Rain Forest Wars
2163 CE
- Formation of ONI
- Argyre Planitia Campaign
2164 CE
- Massive recruitment drives lead to the exponential growth of the armed forces of the UN.
2170 CE
- Callisto Treaty
2291 CE
- Humans achieve FTL through the development of the Shaw-Fujikawa Slipspace Drive, created by its namesakes.
2319 CE
- The Inner Colonies are established as the UNSC attempted to alleviate overpopulation through colonization.
2321 CE
- The ORION/SPARTAN-I project is initiated, and then killed.
2462 CE
- The Unggoy Rebellion begins as a result of tensions between the Kig-Yar and the Unggoy and the failure of the Prophets to enact a proper response. The presence of an Aribter was necessitated, such was the scale of the revolt. The Rebellion was put down in the same year.
2540 CE
- Humans span across 800 worlds of the Orion Arm. Outer Colonies are established and Reach becomes the UNSC's greatest powerhouse of military goods, both mechanical and human.
- The Leviathan of Dis is discovered by another Batarian survey team on the planet Jartar. The Leviathan disappears after a Batarian dreadnought passes through the system.
2541 CE
- The ORION/SPARTAN-I project is restarted in response to attacks by insurgents in the Outer Colonies.
- The Carver Findings are published by Dr. Elias Carver delineating his theory on the oncoming civil war humanity was facing if the Insurrectionists and the Outer Colonies were not soon pacified.
2492 CE
- The Jiralhanae are discovered by the Covenant. Ravaged by years of civil war, the Jiralhanae are quickly indoctrinated into Covenant society.
2494 CE
- Callisto Incident
- An Insurrectionist group seize control of Eridanus II.
2496 CE
- The first Spartan I deployment on Eridanus II was a success.
- UNSC forces attempt to dislodge the secessionist grip on Eridanus II, but fail.
2502 CE
- Operation KALEIDOSCOPE
- The Secessionist Union arises on Harvest, challenging UNSC authority on the planet.
2506 CE
- The ORION/SPARTAN-I project is deactivated.
- A Batarian survey team discover Sovereignin the Perseus Veil.
2511 CE
- John-117 is born.
2513 CE
- Operation: TREBUCHET
2517 CE
- 75 children are kidnapped for the SPARTAN-II program.
2524 CE
- The Kig-Yar manned Minor Transgression happened upon the UNSC Horn of Plenty, which was raided by the avian pirates. The location of Harvest was dredged from the ship.
- Operation: TREBUCHET continues on into the Epsilon Eridani system.
2525 CE
- The SPARTAN-IIs receive their augmentations.
- SPARTAN-IIs deployed in Eridanus Secundus and Jericho VII. Operation: TREBUCHET came to an abrupt halt as the Human-Covenant War erupted.
- Skirmish on Minor Transgression
- War is declared between the Humans and the Covenant when it is discovered that the Humans are the metaphorical "children of the Forerunners." The truth could have potentially led to the dissolution of the Covenant as the San 'Shyuum's basis for their religion was that they were the chosen of the Forerunners. Later, the reason for war was modified so that the humans were accused of sacrilege and defacing Forerunner relics.
- First Battle of Harvest
- Battle of Chi Ceti
- A series of incidents involving Asari craft and Batarian slavers collectively known as the "Asari- Batarian Trafficking Incidents" results in the closure of the Batarian embassy aboard the Citadel after the Batarian Hegemony refuses to acknowledge the events.
2526 CE
- Battle of Alpha Aurigae
- Battle of Bliss
- Battle of Circinius IV
- Second Battle of Harvest
- Harvest Campaign Begins
2528 CE
- Battle of XI Boötis A
- Hegemony funded pirates assault the joint Asari-Turian colony of Oculus. The attack is beaten back by Turian ground forces and the arrival of portions of the Asari, Turian and Salarian navies. The attack further alienates the Batarians, already in a bad light because of their slavery practices.
- Anhur Rebellions begin
2529 CE
- Battle of Hat Yai
2530 CE
- Battle of Groombridge 1830
- The Citadel Council, previously reluctant to engage in hostile activity with a Citadel member, unanimously votes to begin an anti-slavery campaign. The combined naval forces of the Asari, Turians and Salarians begin an assault on Torfan's satellite, obliterating all pirate activity in the area. The campaign results in the destruction of 10 main pirate stations. Since the campaign, slavery has declined significantly.
- The Anhur Rebellions end with the abolitionists triumphing over their pro-slavery adversaries.
2531 CE
- The United Rebel Front attempts to capture SPARTAN Blue Team, but fails as they were unaware of Kurt-051, a new addition to the team.
- SPARTAN-III program is initiated
- Harvest Campaign ends
- Battle of Arcadia
- Battle of Shield World 0459
2534 CE
- UNSC Emergency Priority Order 098831A-1 "Cole Protocol"
- Battle of Meridian
2535 CE
- Battle of Charybdis IX
- Battle of Jericho VII
- Battle of Metisette
- Battle of the Rubble
2536 CE
- Alpha Company receives augmentations and is activated.
- Battle of New Constantinople
2537 CE
- Siege of the Atlas Moons
- SPARTAN-IIIs engage Insurrectionists in the Insurrection of Mamore.
- Operation: PROMETHEUS
- Battle of Leonis Minoris
- Battle of New Harmony
2539 CE
- Beta Company is conscripted
- Battle of Kholo
2540 CE
- Siege of the Atlas Moons
- Engagement at Alpha Cephei
- Raid on Heian
2543 CE
- Battle of Psi Serpentis
- Gamma Company formed
- Battle of 18 Scorpii
2544 CE
- Battle of Miridem
- Operation: WARM BLANKET
2545 CE
- Operation: CARTWHEEL
- Operation: TORPEDO
- Battle of Actium
- Battle of Draco III
2546 CE
- Battle of New Llanelli
- Battle of Sargasso
2547 CE
- The SPARTAN-II program is made public in order to boost morale.
- ONI Directive 930 "Spartans Never Die"
- Battle of Skopje
2549 CE
- Battle of Gamma Pavonis VII
- Fall of Arcadia
- Siege of Paris IV
- The joined efforts of the Salarians, Turians and Asari culminates in the stealth frigate Solidarity, a show of unity amongst the Citadel Council. The ship is crewed by Asari, Turian and Salarian personnel, with the occasional Client Race member. Command is eventually passed onto Spontis.
- Braxis is assaulted by Geth forces. The Solidarity is dispatched to aid in the defense of the colony. The discovery that Spectre Saren was the perpetrator of the attack gradually leads to the startling uncovering of the Reapers' return. The news causes widespread panic, but martial law is enforced by the Council Races who had already prepared for this event. Massive militarization takes place in preparation of the Reapers' arrival.
- The Solidarity hunts down the rogue Spectre, bringing him to justice and revealing that the Reapers planned to use the Citadel as a method of entering Citadel Space. The plan is foiled, delaying the Reapers. This is known as the First Phase of the Reaper War—the Betrayal.
- Spontis is inducted into the Spectres. He is given augmentations, enhancing his speed, reflexes, biotic power, strength, processing speed, memory etc.
- The Collectors are discovered to be a real threat. The Rachni, previously thought to be extinct, are revealed to be under the thrall of the Collectors, who were in turn under the thrall of the Reapers and were attempting to construct a Mass Relay to ferry the Reapers into the Milky Way galaxy. In desperation, Spontis acts and cures the genophage, winning the support of the Krogan against the Rachni. The resulting conflict is known as the Second Phase of the Reaper War or the Krogan Redemption or the Second Rachni War. Results in the destruction of Harbinger.
2550 CE
- Battle of Algolis
2551 CE
- Battle of Ballast
- SPARTAN-IV program begins
- The Second Phase of the Reaper War concludes with the Solidarity leading the charge into Collector space, exterminating the remaining Rachni in a nuclear bombardment of the station housing their queens and the complete destruction of the Collector navy. The Prothean upgrades to Citadel navies and armies results in their increased effectiveness.
- In what is known as the Third Phase of the Reaper War—the Reclamation—Spontis delayed the Reapers' return for a third time. The True Geth reveal that their heretical counterparts were fighting for the Reapers and sought to utilize the super-structure known as the Consciousness to use the Geth against their organic contemporaries. Spontis concludes that he must aid the True Geth in eradicating the Heretic Geth and does so, bringing the Geth out of their isolation. This opens up the Quarian home world Rannoch, allowing the Quarians to resettle the world, bringing the Geth and Quarians into the galactic anti-Reaper alliance.
2552 CE
- Siege of New Alexandria
- Skirmish over Threshold
- Raid on Verge
- Operation: FIRST STRIKE
- Massacre of Troy
- Massacre at Eridanus Secundus
- Battle of Line Installation 1-4
- Battle of New Jerusalem
- Battle of Fumirole
- Fall of Reach
- Raid on Reach
- Battle of Onyx
- Raid on Verge
- Battle of Beta Gabriel
- Battle of Installation 04
- Battle of Installation 05
- Battle of Sigma Octanus IV
- Battle of Ariel
- Great Schism
- Battle of Mare Erythraeum
- Battle of Earth
- Battle of High Charity
- Battle of Installation 00
- Raid on Installation 04B
- The Reapers arrive in force, initiating the Fourth Phase of the Reaper War, the Return.
- Development on the Catalyst is stalled as the Reapers continually hit research facilities.
- The Battle for Palavan is fought. Palavan is lost and the Turians are forced to retreat.
2553 CE
- Battle of Draethus V and the first deployment of the SPARTAN-IVs
- The survivors of Onyx are retrieved from the Dyson Sphere.
- Kilo-Five is created, mostly for anti-Insurrectionist and anti-Covenant Remnant ops, but they are also utilized to keep an eye on the Sangheili.
- The Insurrection was heavily damaged, having engaged the Covenant on numerous occasions as the Covenant made no distinction between UNSC and Insurrectionist. The UNSC begins a covert war against the Insurrectionists.
- The Reapers now cover 30% of the galaxy, and would have controlled more if the Protheans had not been awakened earlier.
2554 CE
- Sangheili Civil War results in the Arbiter's absence. It is a victory for the Arbiter Loyalists but also the formation of the Neo-Covenant.
- Former Covenant species create their own governments
- The Reapers now control 50% of the galaxy.
- The Batarians by this time are under siege by the Reapers and commit their resources to completing the Catalyst.
2557 CE
- UNSC Infinity commissioned
2558 CE
- Sangheili-Jiralhanae War and Jiralhanae Civil Wars begin
- Gray Team is recovered in Covenant Remnant territory.
- The First Battle of the Catalyst is fought over the Catalyst when Reaper indoctrinated personnel reveal the location of the Catalyst. The ensuing battle leaves the 7th Citadel Fleet devastated. Completion of the Catalyst is delayed.
- Renowned scientist Mordin Solus completes the anti-Reaper virus.
2560 CE
- Sangheili-Jiralhanae War ends as Chieftan Bruticus unites the warring tribes under his rule and makes peace with the Elites, seeking to rebuild the Jiralhanae.
- The UNSC Spirit of Fire is recovered by the UNSC Infinity in Neo-Covenant space
- The Second Battle of the Catalyst was fought just as the device was finished.
- The combined might of all the Citadel Races was brought to bear in the Battle for the Citadel, which was under Reaper control. The navies of the galaxy managed to repel the Reapers long enough for the Catalyst to be attached and the virus deployed against the Reapers.
- The 15th Pan-Galactic Reaper War is concluded with the extinction of the Reapers.
- The Citadel grants the Hanar, Elcor and Volus greater autonomy. The Krogan, Quarians, Geth, Protheans and Batarians receive Council Seats for their extreme contributions during the Reaper War.
- Reconstruction begins as half of Council Space was devastated by the Reapers. Reaper technology is utilized to expedite the process and empower Citadel forces. Now, the Citadel is more united than ever, having just survived the greatest threat to galactic security since the Rachni.
2564 CE
- The Geth discover the CCS- battlecruiser Wrathful Retribution
The Aftermath
Halo
- Carter-A259, Catherine-B320, SPARTAN-B312 and Jun-A266 survive the Fall of Reach and are inducted into the Spartan-IV program under the Noble designation. They are serving onboard the UNSC Infinity.
- The surviving S-IIs are being drafted to help train the new S-IVs; they continue to serve in combat. The S-IIIs act as the vanguard of Spartan teams, the proverbial hammer to the S-IIs scythe and the S-IVs sword. Blue Team serves aboard the UNSC Infinity.
- Catherine Elizabeth Halsey is kept on the UNSC Infinity to oversee her Spartans, as well as to examine any Forerunner artifacts that are discovered.
- The Arbiter and the Chief fail to make it through the portal.
- Rtas' a few Arbiter loyalists keep the Sangheili in check, but a there is still anti-human resentment, enough for a sizeable force of Elites to desert and join the Neo-Covenant.
- AI have made significant advancements, becoming more and more powerful with longer and longer life spans. They are also making strides in society, gaining rights.
Mass Effect
- Reconstruction is well on its way with the harvesting of Reaper technology.
- The Citadel Races have reached a level slightly above the Reapers in technology.
- The Geth have been accepted into galactic society due to their remarkable contributions in the Reaper War, and have gained many rights since, becoming full citizens. However, there are some scattered anti-AI dissidents.